SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7129e452397223f7bf1b293e6748811c647dd41f20a5f019f59291757b2c42a1' 
  AND token = 'o7rWVOKwIjXO8TXb+UBVZqTFNv9KKQvurOjCSeFYRWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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