SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dcfa580d9dbe1f21608378b314aff743b64045ecacb434c5d6fa0b3d717034f8' 
  AND token = '4mbZkrX+2r5zC/6CjX1VmwiZ93W0oGuPIkHXu2AkMHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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