SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e96131ee398ac305224199d808a109aa76da7d27651fb6d50b3987433537384' 
  AND token = 'aQxCYYAmw/lksBEv3DB5k1GLS4FLAiKVtZv+4SEhKBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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