SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e357396d8fe4edea2a9171d01fb86243fe18fb707df9b82a65e5ff05145fb91c' 
  AND token = 'digNG+BMIcqHRt9ZTnlpvH02SIu98mXNsygmREV8biE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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