SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dc7d49289e7835e49e70062c462c7167735f6346c9483a686378c2fd499bb88' 
  AND token = 'f9NpaUcZZ2eIzPXwIAuq5ETAsKRnjNQSjwvR5862bv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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