SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c3e4628dd51802fabaa3eb4f5377a42dee658fb02d36aeb66e62bf8a52656fa' 
  AND token = 'Wu0slAIItiXxgbljzryVpdOoDQ15/Qi1abEaoGqDVJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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