SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8120bab74c4eaf0de99aadc92281326d6d27066d55fcf9ba4fa3dae994fa5713' 
  AND token = 'Hw3+WkWQ+RKTGUS23LXUD+5Kgp4vBE0CgIPGLTPuwGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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