SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e11492c2082d6dbba12979406a89004029e6235023e5fba2e2b56f439a23c9b' 
  AND token = '6+yWdrU4aQ5+RajMd2961I+NSverS+4YiyrgpwCaH3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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