SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc688a6422d1e39bb82e3c3c41bcd31fd8c12d82fe9b0205aa7435f0c24adfa5' 
  AND token = 'R2X3rmAH8PBTFDkLldy7Mdf6tFMIBA9NsG3te2CtKx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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