SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a73d49e008a7bc8e63a960811adbea3dc65146f3145b8bef44bbd109462175a9' 
  AND token = 'fgp/3M3xmQj2U22OBh2dbw6jkqPpUPXVnS4ZcmOPBYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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