SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6fcb776395a5aff021821fc58f3ab4b5949fd4497b59d71cf30c6b1994836f9e' 
  AND token = 'RsLpjFSzwPfZsA9wtp/Vc62LmcMmv43JQNa4Nuc0FS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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