SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c94aa258c577398861dbd9966c2aca0aa92b3497cee2d879ec95f151c9676dfa' 
  AND token = 'IImP4j6/c+/r2W/i6SjxOfcOZ4ONT/at9WliJwJ3fLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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