SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57018e4f105076b4d19178d72c5b47791531b7df458b8f77e5f058238bc27a09' 
  AND token = 'GTavPCHfmFmdg6PTwLD/uTSJb5E3CG9s7YqrtEshaFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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