SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b184b0a6d15dff3cef7160805a30e4231a86e069ca7def3eda2bb108b2cd34bf' 
  AND token = '0o3GiouMnlh0OX0w+UR20X7HeN9J+ZkKfP3Kp52yz/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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