SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7231b3160b92e43d753c8b523b24021e049606c85886b500f339d763d5175291' 
  AND token = 'OnaQExGsk91A7h8kfg9TetnfyG2FcUshCJvRRuLZUHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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