SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '367ab0b4cc8ba620e56d5283d0778954579beea6751d418c50043c9e83376aff' 
  AND token = 'BfyVA52ZtyGkaQGP8/LL7EQgir4WKrClJPuaPT/V8EE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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