SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb8efcb8fe36a23da2e8dd646025f00aebedfea8bacd4b3859caac865451637f' 
  AND token = 'XhiczdETe0wwq848Ig6n/Thygpp1z2LpCGANjDQsl+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}