SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fa5f8954548f73d1ebb21336ff6640c2b0e775fadafc7fa7ed3298486b1a30e' 
  AND token = 'H7709hHw/Bfd1ozKfSx9feQ1Zp4vKhkgLcFAdWxlbyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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