SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deb854df93dad12ba84064e9a0ede353bde9139db940729ee5a60d16556bb245' 
  AND token = 'f3+1qfqio3gnyMtyBAuxHAogdGpVptlvqABWbftVVp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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