SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89d4de61e51a42da74c58aac3eff7dbf25a28f6850f3881b130d8e2f80252c76' 
  AND token = 'WTlsz0/XfvvUVRW4tAsvBReG3bhQ3Z+FJP/4uL0acXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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