SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08d932f4526bfad557660cd5302b4739f480cc993348d508c1d561482daa0b11' 
  AND token = 'mWru7SozFpBBFB+PmRVu8QKrfWlgs59LE1/rjOIhqWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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