SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4d3f4e50a767377aabaf32a346d9093409dc97e8df2287211dcf9a3a09cd371' 
  AND token = 'JHLyp9fn5LcRXBxKREt4zW6fo1EuEKNvdMWa+StsSCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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