SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4f5efc119193ca2a3613550f0f04e2a109df825c8baa3222beccb2247b124069' 
  AND token = '9r5NTvGFpipnM8/L5yEJ/mCoVXA6AmODDrpVa4nznZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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