SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7f88e1b79890f5073d997b41663c89fc625f212163aae551d697fdd63275d274' 
  AND token = 'JyXPQq9N5+dizSKMPXGFgLH1/6MXc3yR95xVoQ3Axng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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