SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c7e8311defd0c5902432969e3f921483d3c11fada976059dacd822d981979f4' 
  AND token = 'Y4J/9ScmSv465jGVHeLSuWQC6DtNpg1rMVdhTpgtvuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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