SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f3b570b771c3d10e3432b18f2e21b69d148f937b7431d1a44f160ce852197a8' 
  AND token = '27VM8DFYfByn5AH9dCln+JC3RI8v/gXvITJ2cjE/5vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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