SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c97fed0237b5bf2708912c145f50bcc4c3bbffea21413f263cac4215d5446ec2' 
  AND token = 'wZs6C4ZcYCUmZPWagj7IgehGoGnb8RKWIrI/crx4K44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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