SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b440191d404752f61ca682b432b207f00e8f63c6c5ddf64ca5493e0325642e77' 
  AND token = 'PqGVUBm2QznYpXT7gI65hB+5trzPZ+oQqwZMT9rhnTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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