SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ce4c77265d3ce9858abc39720d8aec96639b78c0cb892eb61b2db45f9e78bab' 
  AND token = 'CSKd/NEkoUkoJtLVzBHxORxF+CUxnVfkPJaJBrnGZJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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