SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aed20cb2029ab0a050d89b66b2ed350711ddc47b5be99d7d19cb0375e79d8b2' 
  AND token = 'UWJn0jDvijRqRPooFOE1D/orRCDnAAp224ayXocO8pI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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