SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00434786f763ef999bebc2efec55b0718996762bb601e82c2721444307e30207' 
  AND token = 'DX87OyMkOx5tKIrkS6OG3arSFXaGszObvsXQnq1URPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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