SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '573e5e9166a82621f2b4f0dc9a75bc08aab2addd3c95269087ad428281e918ff' 
  AND token = 'Odu89dTDVgkwh/W9semDYZjRtwgBw76q8BQLp/0BuxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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