SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79621db1eacca5fac33d925e25cf1c0bcd64dbc78cb98c6eb8edee73ac95e712' 
  AND token = 'MV4mb73dCijmhoA8d9yG/hClhzuaHGHE56qeLzNjLYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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