SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '349665ddfb90552e8c29fae1960cb5f0663cd31c3f29269194e63bca8273f35f' 
  AND token = 'FERU0ujJPwCAA7heVEpg7WU5bBrXXWlCxxHZ0UflQzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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