SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '640bfff1efac621027e763495d3b3b802ac5130767bd14ab1e654ee4bb033c68' 
  AND token = 'Qp2xLkPbGSPAoXkaLRx3lwEc4iqtkSAMuoQoxaoX5gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}