SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0f27438a7ff664cf5b10da1cc3e5852368d4b1d6d0284cc57127bf96c4b534f' 
  AND token = '61yKLnw5zJNsb8eiDXYEU/3la2AnRTu4jwA0twpcIE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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