SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '626ef7fe941e7bab43cfb6a94fd5f38bea093542c41a76a23ff709f0035a5259' 
  AND token = 'dHO6ib8FGZi8mzosCmzPKcL+w4jANrA3Tm0Oq0wfO1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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