SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8a74f92415fc51d0fd8bcda16cfb153c669ec699879a2e8f77e9131fa07c8863' 
  AND token = '970WFoy7xQ2E7x62566FD9mB8qr3jBX3xlHz0s/EfHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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