SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ead3babdb4c7f99364d4d1ef2a944abf5b5c4aba40b552e613bd6aff81d2975b' 
  AND token = 'BDV+iN9xwfmTsQqdjKWp4Bn7chJb0aDncEYf0gzYgBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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