SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca87b84e55ef6a3829e79818a4a91892978cc9ac5e5bade5b6990055c19d1ce2' 
  AND token = 'lFSoCLXDiw5uT2Lywrn+IrPRqef5Kyq+m5ZQ2CQVmMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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