SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '955fd900c31d4e3addb54f8697cad9ac184c8f465c683e3bff0e962b533ebba0' 
  AND token = 'xsGTlHh+dFrvh4a7bMiR6sqtEwukgl6XSkqvYWGVbbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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