SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea68bad5d98975b336137b87fb74ba08986b0489faf561619f44de2aa7df9956' 
  AND token = 'KCKGLp8Yp4FjOWDsoxC0QCL2KOTbK7XaKlIBv7HfIAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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