SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7f1024453fdecccc8cf104fb37deca2ef84d57f3bc2620e8585b9d2f25be779' 
  AND token = 'dbuBgNVUaiEerVLzn91lHiEfkpSO8ve3lp/zCdYbxk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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