SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16027771932990bda1522a893c27204f5ae09370bd2a5a529966785f580c0e23' 
  AND token = 'EjWYwFYnu7mPTKb/tb+4VpXzZH9pp0eG3rje9MSLe5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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