SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52409188f4cc69fd886757cc30409c466229bf138189c9d2628423ec7afd875c' 
  AND token = '64NKeXd5kzwwNzWaCn636fzwvfT3W6SmqvL/u6t6ZQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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