SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94a80529dccffe9042db5b569c21669412527ea1b08b337cfa3d5ad7061ba055' 
  AND token = '/7frJGhN6VaAB5WZ4FHJlriF0njR7zzMDQ7uEfeeQGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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