SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d830f31c418c51ed4f1557d31f3d4f1d5053c8a2c69b73b79bda569f7e16a66' 
  AND token = 'qwncFFAFfSGRZHMUTPCQDHj1vUpSeopyJkDIizvwEhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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