SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdc460bb31e568ac266b8e3abe850291d37ad7a3e9357d1b8f99e709fcb0086e' 
  AND token = 'QpYJ8To2kiU74cKr1PbRvQsq9a8ltRE6HpIOvUPk2Kc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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