SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42c08823bfc370b59402d9f78fa5c9a0b729ab5959f831223176e9bfd9ba2adb' 
  AND token = 'YpwGvQZXaEjG5JIlLbFCDnzUNrmVEFYl0Xh4hTRq3Ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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