SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e0568f82c3a67b81c5ee644259bc7c83dbcaf72f45c6401bae4cb87f51c5d0c' 
  AND token = 'bdGrLR0qmtqa4yeeATSW2dJkjL3SiarGhSj+EmyiGJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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