SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b525e544dc288700c0d43a3ebd974a4b70dd8608eafe06b7158e653481e68d4b' 
  AND token = '74pUtOTea/nVqqcr0kEwoBCtAo1jKR9xGdAV66aejlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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