SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e436eeb3c8dc5b94bb945721af6b3212739bf5becb668e41564f2f0ce44f5fb0' 
  AND token = 'w+790aLhs3KTGKIu1HAE3o0XBNqArVZglHGfe6mvuQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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