SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '206b26d214a177b15973a1560ba4f2849fadac0224fe2e8c8c6bd9ed2f6836ef' 
  AND token = 'nS7hhwYoMlp05WentJYQQWXNtpft+dibJO4cnsWWUcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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