SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e54bb2ad442953145ecca55c2106c2caf29867e03ec21e4c25e132f8df08614' 
  AND token = 'zHPJiyjQoHUZvzBZbjfs+jDp3dpkpLtHbFJtYG0i7MM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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