SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c741ad4ff4611069672f9e97a44a97464fb62460a00a547a0833c7b53ae82a7' 
  AND token = 'B+jMgMCB8MxoL3xyE/WmhrwYtd7kOV1UX0RBQG3uVjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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