SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2df9269afe88a3b1d051f8ca26379fedbc9e0d9b8f1b847487034ebc79b503d5' 
  AND token = 'Ukg1cmVgRL8AOkhPKg1V1mHIhdxFMWhI15QjJPHZ+VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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