SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c718b72b0f42f77238bf8d6118108b43dea9ecb20554c200c58046e67c334eb4' 
  AND token = 'H3M84UgJr4eiLSC4BZdiTR10JKVaZbRQENrZX5mKEv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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