SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '716a36997164f867583bdf1e9feb88d0b707abd66c10badfdb0ef057733ac529' 
  AND token = 'EgnDsEvt7wX93dgrJElzTMIhNqsHACbPU5TP1kDPIcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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