SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd940438220c6035d54f1951f2fbe40070a9bc4b524c38b99c194a176281f5d9b' 
  AND token = 'Z+mYYCCHWtvqttOkCu7/cWlj4gysQohoD9+Q9wJZ2nM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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