SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7cfe3cf11abd9da87466ea059e5678fc0ae926849f1cd92543a21ca3658bea' 
  AND token = '1Rn1TnWBorN0l4mCg6+yZdQzSB7kriFd2FEYRbgdF3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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