SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa653efcf3c3bfa59b351a64643117ffe6787909a6a785d843a8663fd758a1c5' 
  AND token = 'J1mvTAHafgcRayjryG6soEew7AeMopmFBRMXeyFQzsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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