SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e52833c589491e6d86c2d633654e7af1a7f5511cf6bf4299d48dff9d1985c17b' 
  AND token = 'iYiLPHmZ87TaTNqmVsR7oPzAwJfawB1lpgfXDEouQ9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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