SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4117746205085617feb58e89b36f6179e07b82a93560738f27cf13bce9295433' 
  AND token = 'PMrMzzUoQl2GUH67kLCPmPp48gXaxrUKer6p2Y2fatw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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