SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dd13db1d629b1d9845f8045dc7bcfdc75a249a76cc9a4f253e6a9f7cb4f589eb' 
  AND token = 'zlVBP+gIP/hvG+IQDsdkZYlhta/lkk9nenknklJtDCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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