SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c14f4997e4d9b71e925bb62912860c79eeb9d5011a98e1d4a253a6c565f0f9' 
  AND token = 'AkMjtvnt+3Ku9HfjVswY0S/VJzYXYYvfkLKpAH2Oxbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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