SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0689b093fbd39742b1264c5a48864071765d909afdd867434380478d8528ac26' 
  AND token = 'CJveO12fcXL+PxHWYf3uGotkjt++o9UBs/ieGJS9jYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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