SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87d561d65a896e638683e625b237e44ea67c4869693c81255eb508bc743d7a93' 
  AND token = 'frZZPTsMFTAAJajjTVWguGLxFmIbPdbo1b+eUaKBhco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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