SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0251ad0886272b32b39cc0ec579c14ce88267776fa2dd0ccd753a174ed974af4' 
  AND token = 'K5lYyUawZkUUuNGzvHwaYsuaUEA2qRznuUocUb/GHZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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