SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a62e23d0ae671d488de007af48b14fcf5eb06d17708e3b357c8b6628969038b5' 
  AND token = 'AkLFwF+tXDjWZ9whvKjegTng1PRQ5hqsrtzx7Qdz3Vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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