SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1d3faee59f086d2f04909f1527e9bccb73da099c9539f6d06edf6fada736f76' 
  AND token = 'HYSIpSH3reQNdxL7LfU+gGqcEQPDSP6bQbL1qnWvHOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}