SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '033f6e8ec5edc36d2761b2a73b6a8210052069302c46083a82430647a1ba9f63' 
  AND token = 'cMInX8f+om5ASaWaZoDldFZAtAsTFkKSnOVflgkJ5UA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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