SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ec469d6d933638bcb916ad704cbfeec315395b3285e2ef0e999da0e0b0274c4' 
  AND token = '9kyXzrHqcQw25xtO+OBkJcoJYFrEXxU1De9nETu4PVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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