SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d3ad9c1313bf72377a419eeb38059d6a22ee3a4ad459d06e248deb97b99e0f7' 
  AND token = 'v7sqW9oFIOHZTsaFzIw5R8mY0FPbJWcQCNoKjXpomgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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