SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '802c77ca8756a78475367832c3e9a497f6f0567dc995e20c7d889498c0b78a7f' 
  AND token = 'EHPMJyuQVNNdGnHD8FU3+5bCynTnx941lWk0LbffeR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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