SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62f56bfc87d9d3e84eed5c1624e7277704b3df12c7dc899ba0a1f068fb6e80ae' 
  AND token = 'MepLubjkt9N0YDQZlKYjRQ8jMiGt96rePFB40tjoUQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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