SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f249252aa8ea300fd1e5bfa30f5155ef772506b4c776f0c23dce2c743126ccbd' 
  AND token = 'FhPpmB8GUSYDUDHunEQpkB0aNo2PqaBO77WYdMzksdw=' 
  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"
    }
  }
}