SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b69dc6138d5021932fcac0598f4f5b3fbcf6c55c4638d76c36d139f407359a18' 
  AND token = '6lfoyGspNgIAYtnLd58XlISC+pvdGSllBuX2kcXfDDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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