SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bdddc2660da74ea9aacf5398fd2123230ccdffbf41e5513baae07b0751ca96a' 
  AND token = 'mJfnIp1Co3uKasfPsa2gAv679qRpAkbtw47YR1AyD4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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