SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e0e43029c33172695e8c43fa7fc7d0f7bbb2b9d53d45a9d4288dbcd38f45c572' 
  AND token = 'zVBEdyt5YCu5E0ilrNgWEFjOGGUarMLyr/hUyxYU4Tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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