SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c89195c040be12c75eaa4eb0df35ee124fdd60611d7965c27c27ea456c67be34' 
  AND token = 'frai9rarO+qbNz0gOXlMfdL0Xe/82I0sN/Kw1aKSOGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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