SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5468559ce74b516227bc6140dcc50be7c651d2c64358063d0f10e2b96c088179' 
  AND token = 'gKUQ5+JejfmLySBuzARSR2h+RYi12cOGJL4xZwEm/sc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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