SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c788fe61c48836d181c6402dc8fb186d28e0472df346586d6fcae636f4026be2' 
  AND token = 'CPgm846enRzUNjW1gMJ/oPoKuf88XqmbGPZrbBojcJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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